CREATING MULTIPOINT-TO-MULTIPOINT MPLS TREES IN AN INTER-DOMAIN ENVIRONMENT

• US 20090161583A1
• Filed: 12/19/2007
• Published: 06/25/2009
• Est. Priority Date: 12/19/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Boers, Arjen, Wijnands, IJsbrand
• Granted Patent: US 8,355,347 B2
• Time in Patent Office: Days
• US Class Current: 370/256
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/48 Routing tree calculation
• CPC Class Codes: H04L 45/484 using multiple routing trees
• CPC Class Codes: H04L 45/50 using label swapping, e.g. multi-protocol label switch [MPLS]
• CPC Class Codes: H04L 45/507 Label distribution

Abstract

In one embodiment, a method is provided. A first root node of a first Multipoint-to-Multipoint (MP2MP) Multi-Protocol Label Switching (MPLS) tree, advertises to a second root node of a second MP2MP MPLS tree a first label for the second root node to use to send multicast traffic to the first MP2MP MPLS tree. The first root node receives a second label from the second root node for the first root node to use to send multicast traffic to the second MP2MP MPLS tree. Communications are carried out between the first MP2MP MPLS tree and the second MP2MP MPLS tree using the first label and the second label. In another embodiment, apparatus are also provided.

Claims

1. A method comprising:

at a first root node of a first Multipoint-to-Multipoint (MP2MP) Multi-Protocol Label Switching (MPLS) tree, advertising to a second root node of a second MP2MP MPLS tree a first label for the second root node to use to send multicast traffic to the first MP2MP MPLS tree;

at the first root node, receiving a second label from the second root node for the first root node to use to send multicast traffic to the second MP2MP MPLS tree; and

carrying out communications between the first MP2MP MPLS tree and the second MP2MP MPLS tree using the first label and the second label.

2. A method as in claim 1:

wherein the method further comprises establishing a directed Label Distribution Protocol (LDP) session between the first root node and the second root node over a first Point-to-Point (P2P) Label Switched Path (LSP) and a second P2P LSP;

wherein advertising to the second root node the first label includes sending the first label over the directed LDP session via the first P2P LSP; and

wherein receiving the second label from the second root node includes receiving the second label over the directed LDP session via the second P2P LSP.

3. A method as in claim 2:

wherein the first MP2MP MPLS tree is under control of a first service provider;

wherein the second MP2MP MPLS tree is under control of a second service provider, the first service provider and the second service provider being distinct; and

wherein establishing a directed LDP session between the first root node and the second root node over a first P2P LSP and a second P2P LSP includes;

establishing the directed LDP session as an inter-domain session between the first service provider and the second service provider.

4. A method as in claim 1 wherein the method further comprises:

at the first root node, advertising a forwarding equivalency class to the second root node with which to identify a stitched MP2MP MPLS tree, the stitched MP2MP MPLS tree comprising the first MP2MP MPLS tree and the second MP2MP MPLS tree.

5. A method as in claim 1 wherein carrying out communications includes

receiving, at the first root node from the second root node over a directed Label Distribution Protocol (LDP) session between the first root node and the second root node, a packet having the first label;

replicating the packet and sending the replicated packet with a third label to a child node of the first MP2MP MPLS tree.

6. A method as in claim 5 wherein:

the first label identifies the first MP2MP MPLS tree; and

carrying out communications further comprises looking up the first label in a Forwarding Information Base to obtain the third label.

7. A method as in claim 1 wherein carrying out communications includes:

receiving, at the first root node, a packet having a third label;

replicating the packet and sending the replicated packet with the second label to the second root node over a directed Label Distribution Protocol (LDP) session between the first root node and the second root node.

8. A method as in claim 7 wherein:

the second label identifies the second MP2MP MPLS tree; and

carrying out communications further comprises looking up the third MPLS label in a Forwarding Information Base to obtain the second label.

9. An apparatus comprising:

a first network interface, the first network interface connecting to a child node;

a second network interface, the second network interface connecting to a peer node over a directed Label Distribution Protocol (LDP) session;

memory, the memory including a Forwarding Information Base; and

a controller, the controller being configured to;

serve as a root node for a first Multipoint-to-Multipoint (MP2MP) Multi-Protocol Label Switching (MPLS) tree;

advertise to the peer node a first MPLS label, the first MPLS label identifying the first MP2MP MPLS tree; and

receive from the peer node a second MPLS label identifying a second MP2MP MPLS tree, the peer node serving as a root node for the second MP2MP MPLS tree.

10. An apparatus as in claim 9 wherein the controller is further configured to:

receive a first packet from the child node having a third MPLS label;

replicate the first packet and send the replicated first packet to the peer node with the second MPLS label;

11. An apparatus as in claim 10 wherein the controller is further configured to determine a correspondence between the third MPLS label and the second MPLS label by looking up the third MPLS label in the Forwarding Information Base.

12. An apparatus as in claim 10 wherein the controller is further configured to:

receive from the peer node a fourth MPLS label identifying a third MP2MP MPLS tree, the peer node serving as a root node for the third MP2MP MPLS tree

receive a second packet from the child node having a fifth MPLS label; and

replicate the second packet and send the replicated second packet to the peer node with the fourth MPLS label.

13. An apparatus as in claim 12 wherein the controller is further configured to determine a correspondence between the fifth MPLS label and the fourth MPLS label by looking up the fifth MPLS label in the Forwarding Information Base.

14. An apparatus as in claim 9 wherein the controller is further configured to:

receive a first packet from the peer node having the first MPLS label; and

replicate the first packet and send the replicated first packet to the child node with a third MPLS label.

15. An apparatus as in claim 14 wherein the controller is further configured to determine a correspondence between the first MPLS label and the third MPLS label by looking up the first MPLS label in the Forwarding Information Base.

16. An apparatus as in claim 14 wherein:

the first network interface further connects to a second child node; and

the controller is further configured to;

serve as a root node for a third MP2MP MPLS tree;

advertise to the peer node a fourth MPLS label, the fourth MPLS label identifying the third MP2MP MPLS tree;

receive a second packet from the peer node having the fourth MPLS label; and

replicate the second packet and send the replicated second packet to the second child node with a fifth MPLS label.

17. An apparatus as in claim 16 wherein the controller is further configured to determine a correspondence between the fourth MPLS label and the fifth MPLS label by looking up the fourth MPLS label in the Forwarding Information Base.

18. An apparatus as in claim 14 wherein:

the apparatus further comprises a second network interface, the second network interface connecting to a second child node; and

the controller is further configured to;

serve as a root node for a third MP2MP MPLS tree;

advertise to the peer node a fourth MPLS label, the fourth MPLS label identifying the third MP2MP MPLS tree;

receive a second packet from the peer node having the fourth MPLS label; and

replicate the second packet and send the replicated second packet to the second child node with a fifth MPLS label.

19. An apparatus as in claim 18 wherein the controller is further configured to determine a correspondence between the fourth MPLS label and the fifth MPLS label by looking up the fourth MPLS label in the Forwarding Information Base.

20. An apparatus as in claim 9 wherein the apparatus is under control of a first service provider and the peer node is under control of a second service provider, the first service provider and the second service provider being distinct.

21. An apparatus comprising:

a first network interface, the first network interface connecting to a child node;

a second network interface, the second network interface connecting to a peer node over a directed LDP session;

memory, the memory including a Forwarding Information Base; and

means for;

serving as a root node for a first Multipoint-to-Multipoint (MP2MP) Multi-Protocol Label Switching (MPLS) tree;

advertising to the peer node a first MPLS label, the first MPLS label identifying the first MP2MP MPLS tree; and

receiving from the peer node a second MPLS label identifying a second MP2MP MPLS tree, the peer node serving as a root node for the second MP2MP MPLS tree.